The Roman History · Amm. 21.10.3

The summits of the mountain chains of Hæmus and Rhodope, the first of which rises up from the very banks of the Danube, and the other from the southern bank of the river Axius, ending with swelling ridges at one narrow point, separate the Illyrians and the Thracians, being on the one side near the inland Dacians and Serdica, on the other looking towards Thrace and the rich and noble city of Philippopolis. And, as if Nature had provided for bringing the surrounding nations under the dominion of the Romans, they are of such a form as to lead to this end. Affording at first only a single exit through narrow defiles, but at a later period they were opened out with roads of such size and beauty as to be passable even for waggons. Though still, when the passes have been blocked up, they have often repelled the attacks of great generals and mighty armies.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
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